There is a body of scientific belief that much air pollution results from smoke thrown into the air as a product of burning fuels, leading to acidification of rain and lake water, and the suspension of particulate matter in the air. Therefore, many believe that it is important for atmospheric purification to provide scrubbers for industrial smoke stacks. Many efforts have been made in the past to provide scrubbers of one kind or another to meet these objectives.
For example, as far back as Raymond, U.S. Pat. No. 467,264 Jan. 19, 1892, for "Method of Purifying Smoke" describes apparatus involving a spray of water and steam through which the smoke is circulated, particulate matter being wetted and thus dropped by gravity, and so washed from the smoke. Pridham, U.S. Pat. No. 554,348 Feb. 11, 1896 for "Smoke Condenser" describes a helical conveyor with a scoop to gather in water from an intake pool with which the smoke is to be commingled. After cleaning the wash water the smoke is discharged at an outlet pool, and the wash water is drawn off and fresh water is admitted to the intake pool from which the water is scooped.
Pridham, U.S. Pat. No. 601,677 Apr. 5, 1898 for "Method of and Apparatus for Condensing Fumes or Gases" suggests an archimedes pump for pumping wash water through a brush arrangement to form a spray, the smoke passing through several chambers to be washed and condensed by the spray water. Theisen, U.S. Pat. No. 709,527 Sept. 23, 1902 for "Process of Treating Gases" proposes a drum rotating in one direction into which gases are fed in one sense and water in another so that they counterflow along a thin film in a spiral path on the inner surface of the drum or casing. Sahlin, U.S. Pat. No. 804,677 Nov. 14, 1905, for "Gas Purifier" suggests a drum at the top of which jets of water 8 "play against the drum". The gas to be washed flows through different sections of the drums, passing through dividers wet by the spray.
Baldwin, U.S. Pat. No. 911,802 Feb. 9, 1909, for "Apparatus for Separating Heavy Particles from Air and Other Gases" proposes a blower forcing the gas to be treated through a wire mesh which is wet with water or steam to wash out the heavier particles. Flowwel, U.S. Pat. No. 916,647 June 29, 1909, for "Gas Purifier" suggests using a turbine wheel against which a water nozzle injects water to drive the wheel and collects the smoke to be cleaned by the water at the outlet of the turbine wheel. In Johnson, U.S. Pat. No. 1,289,797 Dec. 31, 1918 for "Smoke Washer" the patentee suggests conveying the smoke by a pipe to the bottom of a pool of water whence it rises to pass through vanes to commingle the by-products with the water to wash the smoke.
Schmieg, U.S. Pat. No. 2,212,752 Aug. 27, 1940, for "Method of and Apparatus for Removing Foreign Material from Air" describes a machine for washing smoke comprising a pool from which a rapidly rotating perforated wheel picks up liquid and throws the liquid against a curved member 68 to break up the liquid into a spray. The spray is thrown against a baffle from which it drains into the pool for re-circulation. The air to be cleaned is forced through the wheel perforations and through the spray for cleaning.
Getzin, et al, U.S. Pat. No. 3,252,691 May 24, 1966, for "Gas Cleaning Apparatus" shows a continuously driven porous medium belt which travels a horizontal, then an upward, and then a downward path. A spray of cleaning liquid is directed against the belt on its horizontal path and also as its path is changed from horizontal to upward. The gas to be cleaned is forced through the liquid moistened belt for cleaning. The medium of the belt 28 is described as of compressible-expansible elastic foam polyurethane material. Holler, Jr. U.S. Pat. No. 3,615,248 Oct. 26, 1971, for "Smoke Control System" describes a smoke filter comprising cartridge filters carried with other filter cartridges in a rotatable drum assembly. Each filter is rotated to a position wherein the gas passes through it for cleaning by a spray of water which may contain calcium carbonates, and then a succeeding filter is moved to the position to intercept the gas flow for cleaning, while the prior used filter cartridge is being cleaned. Gething, U.S. Pat. No. 3,714,764 Feb. 6, 1973, for "Boiler Flue Gas Scrubber" describes an apparatus in which the gas to be cleaned is driven to flow between a revolving helical auger-like member and a simultaneously revolving surrounding drum having a film of pollutant absorbing liquid disposed on its inner surface in counter flow to the gas. The liquid is carried into and out of a sump by means of pump vanes carried by the drum. The liquid may be chemically treated to react with various pollutants.